WASHINGTON - President Obama will name Julia Pierson, a longtime U.S Secret Service agent, as his first female director of the agency, according to a senior administration official.

The official spoke on the condition of anonymity because the announcement hasn't been officially made. The president is expected to a make a formal announcement later Tuesday.

Pierson, 53, now serves as the service's chief of staff.

Pierson's appointment comes nearly a year after the agency -- charged with protecting the president -- was rocked by a prostitution scandal. Several agents, who traveled to Cartagena, Colombia, to do advance work for Obama's visit last April, brought prostitutes back to their hotel rooms.

Secret Service Director Mark Sullivan announced his retirement last month after a nearly three decade career and seven years as head of the agency.

In testimony before Congress last year, Sullivan apologized for the conduct of Secret Service personnel in Colombia.

Pierson was appointed to the position of Chief of Staff on August 3, 2008. Prior to her appointment, she served as the Secret Service's assistant director of the Office of Human Resources and Training, a position she held since June 2006.

She is a native of Orlando and began her career with the agency in 1983 as a special agent assigned to the Miami Field Office, after having served three years as a police officer in Orlando.